Charlotte, North Carolina (CNN) – In his address Thursday at the Democratic National Convention, Vice President Joe Biden will vouch for President Barack Obama's character and leadership through anecdotes about his decisions in office, according to a Democratic source.

As someone by the president's side for his major decisions in office, Biden will draw contrasts between Obama and Republican presidential candidate Mitt Romney, the source said.

However, the address is not expected to be a blistering red-meat stump speech like those the vice president is known for on the campaign trail.

Biden practiced his speech on the convention stage Wednesday night after the official business of the convention ended and then did a walk through of the arena, the source said.

He did not return to his hotel until after 2 a.m.

Biden and the president exchanged speeches and the vice president is expected to tee up the president's remarks about the future of the United States that will close the three day long gathering of Democrats.